When the C ++ vector implements a two-dimensional array, what is the problem of the type operator & quot; To be input in the Class header file ?, Vector two-dimensional array

When C ++ vector is used to implement a two-dimensional array, when defining the Class header file, what is the problem of "type character should be input ?, Vector two-dimensional array

As shown in the following figure, When I define a two-dimensional vector in the class declaration file, I am prompted to enter a type specifier;

 

However, with the same format definition, modifying the two-dimensional vector in the class to the definition in the source file can be passed smoothly and printing can be executed smoothly.

 

The output is as follows:

Hope you can solve this problem!